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Titolo:
PHARMACOLOGICAL COUPLING AND FUNCTIONAL-ROLE FOR THE MUSCARINIC RECEPTOR SUBTYPES IN ISOLATED CELLS FROM THE CIRCULAR SMOOTH-MUSCLE OF THE RABBIT CECUM
Autore:
CUQ P; MAGOUS R; BALI JP;
Indirizzi:
UNIV MONTPELLIER 1,FAC PHARM,INSERM,CJF 9207,BIOCHIM MEMBRANES LAB,15AVE CHARLES FLAHAULT F-34060 MONTPELLIER FRANCE
Titolo Testata:
The Journal of pharmacology and experimental therapeutics
fascicolo: 1, volume: 271, anno: 1994,
pagine: 149 - 155
SICI:
0022-3565(1994)271:1<149:PCAFFT>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
ADENYLATE-CYCLASE; LONGITUDINAL MUSCLE; RAT; ANTAGONIST; INHIBITION; MEMBRANES; ACCUMULATION; HYDROLYSIS; GENERATION; ILEUM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
33
Recensione:
Indirizzi per estratti:
Citazione:
P. Cuq et al., "PHARMACOLOGICAL COUPLING AND FUNCTIONAL-ROLE FOR THE MUSCARINIC RECEPTOR SUBTYPES IN ISOLATED CELLS FROM THE CIRCULAR SMOOTH-MUSCLE OF THE RABBIT CECUM", The Journal of pharmacology and experimental therapeutics, 271(1), 1994, pp. 149-155

Abstract

The regulation of isolated smooth muscle cells from the circular layer of the rabbit cecum by muscarinic receptors was studied in this paper. Binding of N-[H-3]methylscopolamine was found to be specific, saturable (maximal binding capacity of about 325,000 sites/cell) and of high affinity (dissociation constant [K-D) of 0.52 +/- 0.12 nM] The muscarinic M(1)-selective antagonist pirenzepine (PRZ), the muscarinic M(2)-selective AF-DX 116 -dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one) and the muscarinic M(3)-selective para-fluoro-hexahydro-sila-difenidol (p-F-HHSiD) inhibited N-[H-3]methylscopolamine binding with respective inhibition constants (K-i) of (in nanomolar): 1018 +/- 382, 254 +/- 76 and 916 +/- 305. [H-3]inositol phosphates accumulation was increased by carbachol (CCh) (EC(50) of 3 +/- 1 mu M). Antagonists competitively inhibited the CCh-induced [H-3]inositol phosphates accumulation with the following order of potency: atropine > p-F-HHSiD > PRZ > AF-DX116. in addition, CCh increased inositol-1,4,5-trisphosphate level ina time- and concentration-dependent fashion (EC(50) of 1.5 +/- 0.5 muM). CCh inhibited both isoproterenol- and forskolin-induced cyclic AMP accumulation in isolated smooth muscle cells. Moreover, CCh inhibited forskolin-stimulated adenylate cyclase activity in smooth muscle homogenates (EC(50) of 10.0 +/- 22.1 mu M); the CCh-induced inhibition offorskolin-stimulated adenylate cyclase activity was reversed significantly by atropine and AF-DX 116, whereas PRZ and p-F-HHSiD were ineffective. In contraction experiments, CCh reduced the mean cell length (EC,, of 3.94 +/- 1.23 pM). The order of potency of antagonists for the inhibition of the CCh-induced contraction was atropine > p-F-HHSiD > PRZ > AF-DX 116. In conclusion, our data suggest that smooth muscle cells isolated from the circular layer of the rabbit cecum contain M(2) and M(3) muscarinic receptor subtypes coupled to different transductionpathways (adenylate cyclase inhibition and phospholipase C activation, respectively). Moreover, the direct myogenic effect of CCh on cell contraction is mediated through interaction of the agonist with muscarinic M(3)-subtype receptors.

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Documento generato il 04/12/20 alle ore 20:02:59